2026/05/08 by Valeri V. Makarov, Phil Cigan, Kyle Corcoran · 1 voice
Physics and Astronomy · #Astrometry #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Peculiar velocity #Position (finance) #Position angle #Proper motion #Radial velocity #Radio Astronomy Observations and Technology #Reference frame #Rest frame #Very-long-baseline interferometry #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/ae62f4
published in The Astrophysical Journal 1003(2), 209 (IOP Publishing)
openalex created_date 2026/05/14 · openalex publication_date 2026/05/26 · openalex updated_date 2026/08/05
Abstract Our knowledge of the space velocity of Messier 87, which is the dominant galaxy in the Virgo cluster, has been limited to the radial velocity component. Using a cadence of precision position measurements with the global geodetic very long baseline interferometry system over 28 yr, we determined the proper motion vector of the radio-emitting core by a robust statistical method involving 1-norm optimization and bootstrapping. The proper motion vector is directed at a position angle 189 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>°</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 2 ± 3 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>°</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 5 in the equatorial International Celestial Reference Frame, and its magnitude is 10.19 μ as yr −1 with an uncertainty of 0.64 μ as yr −1 . The projected velocity of the active galactic nucleus in the tangential sky plane is (787 ± 50) km s −1 . The peculiar velocity of Messier 87 with respect to the preferred rest frame of the cosmic microwave background field is approximately 1037 km s −1 (assuming a distance of 16.1 Mpc) with an angle of 65° to the current line of sight, which implies a tangential relative motion of M87 and the Galaxy. The peculiar velocity of M87 is directionally concordant with the reconstructed and ΛCDM-simulated motion of the Virgo filament towards the Great Attractor, but the Milky Way moves slower by 470 km s −1 in that direction.